1. Field of the Invention
The present invention relates to an optical encoder, a motor, and a motor system.
2. Discussion of the Background
Heretofore, there has been an optical encoder wherein, in order to detect the absolute angle of the rotation axis of a rotator, multiple concentric annular slits decentered as to the rotation center of the rotation axis are formed on a rotation disc, the decentered amount of this concentric annular slits is detected, and the absolute angle of the rotation disc is detected from the decentered amount thereof (see Japanese Patent Application No. 2007-223499 (Japanese Unexamined Patent Application Publication No. 2009-058243)). That is to say, upon the concentric slits being rotated around the rotation axis, the concentric slits thereof are formed in a decentered manner as to the rotation axis, and accordingly, distance from the rotation axis to the detected position of a concentric slit changes according to the rotational angle. Therefore, according to this optical encoder, the rotational angle of the optical disc is detected according to this distance.